In general, environmental pollution can be classified into air pollution, water pollution and soil contamination, and these are closely connected in that contaminants are transferred therebetween. In particular, soil contamination, which has been caused by sewage waste or atmospheric heavy metals, can pose a serious threat to food production. In industrial area, sewage and heavy metal-containing smoke from plants caused serious soil contamination.
In order to remediate contaminated soil, various soil remediation systems and methods have been developed. FIG. 1 is a block diagram showing one example of a conventional method for remediating contaminated soil. As can be seen therein, the method comprises: a stirring step of adding a cleaning solution to contaminated soil and stirring the mixture; four-stage separation and washing steps of separating soil particles from the stirred soil; three steps of washing the fine soil particles by spraying cleaning solution at high pressure; first and second fine particle separation steps of separating a large particle size from the soil; a precipitation step of adding mixed cleaning solution to the soil and precipitating the soil particles; and a filtration step of filtering the cleaning solution from the soil resulting from the precipitation step.
Briefly, contaminated soil is washed with a medium (cleaning solution, etc.) at high pressure while soil is separated and precipitated according to particle size, and the cleaning solution is filtered out.
However, the wet soil washing method has some problems, such as complex remediation process, large facility size, and producing heavy metal contaminated cleaning solution due to using the cleaning solution.